Solid fuel heating unit



FIG. 1 is a perspective view of a solid fuel heating unit showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a right side view thereof; and,

FIG. 7 is a left side view thereof.

The crosshatching shown in FIG. 2 is partially shown for ease of illustration and is understood to continue throughout the areas indicated. 

The ornamental design for a solid fuel heating unit, as shown and described. 